Re: [PATCH v2 1/1] target-ppc: fix rlwimi, rlwinm, rlwnm for Clang-9

[David Gibson <david@gibson.dropbear.id.au>]

[-- Attachment #1: Type: text/plain, Size: 3264 bytes --]

On Tue, May 05, 2020 at 02:38:17PM -0400, Daniele Buono wrote:
> Starting with Clang v9, -Wtype-limits is implemented and triggers a
> few "result of comparison is always true" errors when compiling PPC32
> targets.
> 
> The comparisons seem to be necessary only on PPC64, since the
> else branch in PPC32 only has a "g_assert_not_reached();" in all cases.
> 
> This patch restructures the code so that the actual if/else is done on a
> local flag variable, that is set accordingly for PPC64, and always
> true for PPC32.
> 
> Signed-off-by: Daniele Buono <dbuono@linux.vnet.ibm.com>

That's a bit nicer, thanks.  Applied to ppc-for-5.1 in place of the
earlier version.

> ---
>  target/ppc/translate.c | 24 +++++++++++++++++++++---
>  1 file changed, 21 insertions(+), 3 deletions(-)
> 
> diff --git a/target/ppc/translate.c b/target/ppc/translate.c
> index 807d14faaa..338529879f 100644
> --- a/target/ppc/translate.c
> +++ b/target/ppc/translate.c
> @@ -1882,6 +1882,7 @@ static void gen_rlwimi(DisasContext *ctx)
>          tcg_gen_deposit_tl(t_ra, t_ra, t_rs, sh, me - mb + 1);
>      } else {
>          target_ulong mask;
> +        bool mask_in_32b = true;
>          TCGv t1;
>  
>  #if defined(TARGET_PPC64)
> @@ -1890,8 +1891,13 @@ static void gen_rlwimi(DisasContext *ctx)
>  #endif
>          mask = MASK(mb, me);
>  
> +#if defined(TARGET_PPC64)
> +        if (mask > 0xffffffffu) {
> +            mask_in_32b = false;
> +        }
> +#endif
>          t1 = tcg_temp_new();
> -        if (mask <= 0xffffffffu) {
> +        if (mask_in_32b) {
>              TCGv_i32 t0 = tcg_temp_new_i32();
>              tcg_gen_trunc_tl_i32(t0, t_rs);
>              tcg_gen_rotli_i32(t0, t0, sh);
> @@ -1933,12 +1939,18 @@ static void gen_rlwinm(DisasContext *ctx)
>          tcg_gen_extract_tl(t_ra, t_rs, rsh, len);
>      } else {
>          target_ulong mask;
> +        bool mask_in_32b = true;
>  #if defined(TARGET_PPC64)
>          mb += 32;
>          me += 32;
>  #endif
>          mask = MASK(mb, me);
> -        if (mask <= 0xffffffffu) {
> +#if defined(TARGET_PPC64)
> +        if (mask > 0xffffffffu) {
> +            mask_in_32b = false;
> +        }
> +#endif
> +        if (mask_in_32b) {
>              if (sh == 0) {
>                  tcg_gen_andi_tl(t_ra, t_rs, mask);
>              } else {
> @@ -1973,6 +1985,7 @@ static void gen_rlwnm(DisasContext *ctx)
>      uint32_t mb = MB(ctx->opcode);
>      uint32_t me = ME(ctx->opcode);
>      target_ulong mask;
> +    bool mask_in_32b = true;
>  
>  #if defined(TARGET_PPC64)
>      mb += 32;
> @@ -1980,7 +1993,12 @@ static void gen_rlwnm(DisasContext *ctx)
>  #endif
>      mask = MASK(mb, me);
>  
> -    if (mask <= 0xffffffffu) {
> +#if defined(TARGET_PPC64)
> +    if (mask > 0xffffffffu) {
> +        mask_in_32b = false;
> +    }
> +#endif
> +    if (mask_in_32b) {
>          TCGv_i32 t0 = tcg_temp_new_i32();
>          TCGv_i32 t1 = tcg_temp_new_i32();
>          tcg_gen_trunc_tl_i32(t0, t_rb);

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]